docs: def asDigraph(self):
          """
          Generate a L{graphviz.Digraph} that represents this machine's
          states and transitions.
  
          @return: L{graphviz.Digraph} object; for more information, please
              see the documentation for
              U{graphviz<https://graphviz.readthedocs.io/>}
  
          """
          from ._visualize import makeDigraph
          return makeDigraph(
              self._automaton,
              stateAsString=lambda state: state.method.__name__,
              inputAsString=lambda input: input.method.__name__,
              outputAsString=lambda output: output.method.__name__,
          )